1. Field of the Invention
The present invention relates to a method for producing an unsaturated aliphatic primary amine that involves subjecting an unsaturated aliphatic nitrile to hydrogen reduction to produce an unsaturated aliphatic primary amine with a high amine conversion rate and iodine value retention rate; and to an unsaturated aliphatic primary amine produced by the method for producing an unsaturated aliphatic primary amine.
2. Description of the Related Art
Unsaturated long-chain aliphatic primary amines are useful substances that find various applications as intermediates of surfactants, dispersants, agricultural chemicals, disinfectants, antistatic agents, textile treating agents, etc.
In general, it is known that amines having long-chain alkyl chains are produced by subjecting long-chain aliphatic nitrites, derived from natural fats and oils, to hydrogen reduction, by which a mixture of primary, secondary, and tertiary amines are obtained.
In the reaction where unsaturated long-chain aliphatic nitrile is subjected to hydrogen reduction using a hydrogenation catalyst to convert to an unsaturated long-chain aliphatic primary amine, promotion of reduction reaction of a nitrile group to an amino group results in the increase of hydrogenation rate of unsaturated bonds in hydrocarbon chains. As a result, in addition to the unsaturated long-chain aliphatic primary amine, a saturated long-chain aliphatic primary amine is obtained as a by-product. Therefore, unsaturated long-chain aliphatic primary amines cannot be obtained in high selectivity. On the other hand, if hydrogenation rate of unsaturated bonds in hydrocarbon chains is reduced, it is difficult to obtain an unsaturated long-chain aliphatic primary amine in high selectivity.
As a method for producing an aliphatic primary amine by is hydrogenating nitrile compounds, methods disclosed in Japanese Patent Application Publication (JP-B) No. 38-21353 and Japanese Patent Application Laid-Open (JP-A) 04-266859. In the method disclosed in JP-B No. 38-21353, the aliphatic primary amine is produced using a hydroxide of alkali metal or alkaline earth metal, or an alcoholate or amide of those metals. Specific products disclosed are amines having 5 to 9 carbon atoms. The method disclosed in JP-A No. 04-266859 is related to the production method of saturated aliphatic primary amine. Since the primary amines prepared by these methods have a high solidification point (pour point), there are problems. Particularly when derivatized primary amines are used, they are difficult to handle.
To solve this problem, a method for producing an unsaturated aliphatic primary amine with a low pour point is proposed (See JP-A No. 2001-226327). The method described in JP-A No. 2001-226327, however, may generate a saturated long-chain aliphatic primary amine as a by-product as a result of hydrogenation of unsaturated bonds in hydrocarbon chains. In addition, when an aliphatic amide is added, it is difficult to remove by filtration after the reaction, and turbidity, scum, or the like may be generated in the products.
Thus, in the present situation, a method that suppresses the generation of saturated aliphatic primary amine as a by-product, does not generate turbidity or scum in the product, and can produce an unsaturated aliphatic primary amine with a low solidification point efficiently has not been provided, and there is a desire for further improvement.